Electric furnace.



M. APPEL.

ELECTRIC PURNACB. APPLIUATION FILED SEPT. 9, 1911.

1,01 3,359. Patented .121112, 1912.

2 SHEETS-SHEET 2.

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"uesrsim Bulimie-4 ons, ma l ELECTRIC* rtriamrcna. f

B e it known ,that I, Moses a citizen Vof the United States,residing-at- Balti-v more, lin th'e State of Maryland, have invented-certainnew end useful Improvements in Elect'ric. ,Furna ces., of whichthe 'following is a specification. 4 Y

'the object-fof the invention beingthefpro- This invention relates ,toelectric furnaces,

visi Qf'an eilicient furnace of :theresistancA pe adapted `'primarilyfor the refining of7 iron, steel, ferro-alloys and;` other metals,although capable of use for the pro-pl duction from their ores o f iron,ferro-alloys,- Zinc and other metals@ The furnace .may also be used inthemanufactureof glass.

Thev invention lwill be 'described by.4 reference to the accompanyingjdrawings illustrating oneembodiment thereof, wherein Figure 1 is an endelevation of the furnace; Fig. 2 is ahor'izontal section on line 2-2 ofFig. 1; Fig. B isa transversevertical section on line V3 3 of 'Fig.'2';.jand Fig. 4 is a vertical longitudinal section on line 4-4 of Fi3. c

'Izhe furnace shown comprises a refractory furnace body 1, supported bya metal Vshell Band suitably mounted upon curved rails or beams 3carried by*` a stationary sup- 'port 4. These features of constructionmay conform to the approved practice ,in tilting open-hearth furnaces,Athe indications of the drawing being 4more or Aless;diagrammatic incharacter.

The terminals-or electrodes 5, G enter the ends of thefurnaceand, forthe manufacture of crucible or other high-grade steel,

are preferably of metal of like character, being composed vin this caseof `wrought iron or steel. posed one or more main bodies or baths 7 ofthe metal to be refined. `Three suchybaths are indicated, althoughalarger or smaller number may be' provided.l Each of .these bodies isconnected by a' tap hole 8 with the spout 9, in such manner that themolten metal may'be pouredfromthese baths by tilting the furnace at asufficient angle.

f 8 is a refracto plug.

The several mam baths 7 are partly 'sep-f arated from each other bypartial partitions 10 of vhighly vrefractory material, having providedtherein open channels 11, which extend below the normal level 12 of. themolten metal, in such manner as to provide interconnecting metal bodiesof reduced cross- -connectiom Similar electrodes 5, 6.- f

Between the, electrodes are dis-` L spammen@ 'of Margraten-.1 PatentedJn, 2,1912, fljagpncaaonniee september a, 1911. y 1

- serial No. 648,426.

the molten bath, whereby the surface portions only of the main baths arein metallic .arate the end baths of the series from the 13, 13 representcooling pipes for cirof the electrodes 5, 6. 'These-electrodes aresutliciently cooled to guard against melting thelr outer ends, while theinner portions of partialpartitions Sep section as compared with `thatofthemain .baths 7. As illustrated, the contracted the-electrodes may befluid in the normaloperation of the furnace. In eneral, the portion' ofvthe electrode which Aextends 'through the furnace wall. should bel of assmall cross-section as is'consistent with the current to be carried, andshould be operatedat such temperature as will afford the bestheat-economy, as i'swell .understood in the The protruding ends of theelectrodes may be connected in an electrical circuit of any appropriatecharacter and in any desired way. Thus a direct or alternating currentof appropriate volume may be passed through the molten metal, or theconstruction may be adapted for use with a. twoor three-phase current,orv induced currents may be used.- Thus as illustrated in Figs. 1 and 2,the terminals 5, 6 may be connected by a short, heavy copper lead 14, ofs'uilicient cross-section to carry the lcurrent without undue heating,this lead traversing a primary coil 15, whereby the molten contents ofthe furnace' and the lead 14, together with the electrodes, constitute aclosed heating secondary circuit. As shown, the coil 15, is so carriedupon the furnace body b v brackets 16. with appropriate insulation 17 asto avoid interference with the tilting or pouring operation.

In operation,I lthe furnace is charged with metal, usually in a, meltedstate, and by passage ofthe current the metal is broughtl to therequired temperature and so maintained for the required time, vwith theaddition if desired of the usual reagents employed for the production ofrefined or alloy-steels. The heat is chiefly developed in the contractedpassages between themain baths of metal and 'between these baths and theelectrodes or terminal bodies of metal, and is transferred largely by`conduction; assisted by any natural circulation of metal. In this mannerit is practicable maybe varied and controlled by merely tiltifurn'acefor the production of various carbon l direction of the brokenarrow will have the to bring the entire mass'ofmetal to any del siredtemperature below the melting point of the lining of the contracted'channels. p AIt will be noted that in the construction illustrated 'the'contracted channelsor passages 11 are located at one side of the centervplane of the furnace. Owing to this construction, the cross-section ofmetal 1n these passages or channels varies w1th every position ofthe-furnace; and` conversely,I 'the cross-section lof metal in thesechannels, andl hence its temperature under constant current conditions,and with it the-temperature of the Ventire metal contents of thefurnace,

ing the furnace. Thus if the furnacebe tilted in the direction of thesolid arrow, Fig. 3, the effect will be to diminish the cross-sectionalarea of metal in ea'ch 'channel' 11 and to increase correspondingly theheat` ing effect of the current; while tilting in the contrary effect.In other words, the temperature of the furnace rma be accuratellcontrolled, regulated or. varied, at 'the'w' of the operator, bytiltingit'forward or backward asconditionsmay require. -Any arrangement ordisposition of the channels to secure this result may be used.

The 'process as above described presentsv several important-advantages:

(1) Although depending forthe development of heat. u on the resistanceof the molten metal, it 1s very compact for a given capacity, wherebythe radiation losses are minimized.

(2) The expense of carbon electrodes as well as the laborcost ofrepairing and renewing such electrodes is avoided. At the same time allcontamination of the 'bath by carbon is prevented, permitting thefurnace to be employed for the manufacture of highgrade orcruciblesteels.

(3) The temperature of the furnace may l be regulated with greaternicety and through a wider range than is the case with ordinary arc orresistance furnaces, ;by merely tilting the furnace, with or -withoutthe simultaneous control of the heating circuit. In case constanttemperatures are required, a thermostatic control of the furnacetemperature isv easily rovided, it being merely, necessary that t eposition of the furnace should be automatically adjusted in accordancewith the temperature indications.

(4.) The furnace presents certain special advantages relating to themanufacture of steel. For instance, assuming the-metal to have beenpoured into the furnace and refined -to the required degree, the furnacemay be slightly tilted in the proper direc-- tion for pouring, wherebythe temperature is further increased, and the metal brought l baths.

to fluid.: condition. Athe same time,.. if,1des ired, the flow ofcooling water vmaybe"iiicreasd, in order to solidi all, or

-theprincipal portion, of the' termina masses 5, 6. Under theseconditions the furnace mayr be `discharged without lossof the materlalof tle electrodes. By removing the plug 8 a""branch circuit isestabhshed throughtaps, 8, to maintain the proper fluidity ofmetal'therein.

For the retiningof'non-ferrous metals the internal structure may remainas above de' scribed,` the electrodes beingv constructed ofsuchimaterials, as for example iron, carbon or copper, as may presenta'dyantages under particular conditions. e

This furnace can also be used as a heating and'other compounds. Theconstruction of the furnacewould betheA same as for the 'manufacture-ofsteel, b ut the spaces occu- Avpied by Steel would be occupied by iron,silica or other material which would act as a resister and.l also as aconductor of heat.

jIt.would,beh'eated to high temperature as *described-'under therefining of steel. The carbon -or'` otherv `material would then beaddedlat the top of the molten resister and heated by.conduction from itto any desired temperature.'` VAny gases'or other' materials desiredcould be passed through the furnace and the variouscompounds made.

It is to be understood that the invention is not limited to the detailsof construction herein described by way ofillustration, and that` theform',.size` and proportion of the `parts `may be varied according tothe character of material treated and the scale of operations.

I claim 1. VAnelectric resistance furnace'mounted' for oscillation andcomprising a plurality of metal baths electrically interconnected atAtheirsurfaces, in combination with metallic electrodes lin conductiverelation with said 2. An electric resistance furnace mounted foroscillationgsaidfurnace comprising a plurality of metal bathselectricall interconnected by relatively contracted c annels, saidchannels so 'arranged that the crosssectional area of conductor thereinmaybe i varied by tilting/thc` furnace.

3. An electric resistance furnace mounted for "oscillation and"comprising oppositely -disposed electrodes and a plurality ofintermediate metal baths, vsaid baths electrically interconnected attheir surfaces by channels of relatively small cross-'sectional area.

'4. An electric resistance furnace mounted for A oscillation andcomprising oppositely disposed electrodes and a plurality ofintermediate metal baths, said baths -electri- 'cally interconnected bychannels of relatively small cross-sectional area and so disposed thatthe cross-sectional area of the interconnected metal baths,

varied by tilting furnace mounted comprising electrically and electrodesin conductive contact therewith, a conductor connecting said electrodessecondary circuit, and a to form a closed primary Winding 10 supportedby the furnace in inductiye relation to saidsecondary circ 6. Anelectric reslstance uit.

furnace mounted for oscillation and comprising a plurality of main bathsoi metal electrically interconnected at their surfaces, electrodes inconduc-` 15 tive relation to the end baths, and a metaltap for each ofsaid main baths:

In testimony whereof I aix my signature in presence of two witnesses.

MOSES APPEL. Witnesses:

W. H. PAmo, HARRY B. KINGER.

